JP6659676B2 - Cutting insert, cutting tool, and method of manufacturing cut workpiece - Google Patents

Description

  The present disclosure relates to a cutting insert, a cutting tool, and a method of manufacturing a cut product, and more particularly, to a cutting insert having a coating layer on a surface of a substrate.

  As a cutting tool, a cutting insert in which a coating layer is formed on the surface of a substrate such as a cemented carbide or a cermet to improve wear resistance, slidability, and fracture resistance has been widely used. It is also known to form a C surface (chamfer honing) or R honing on the cutting edge portion of the cutting insert to increase the strength of the cutting edge.

  For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 10-43912), a coating layer such as a TiAlN layer is formed on the surface of a substrate made of cemented carbide, and an angle between the rake face and the rake face is 20 to 30 degrees. A cutting insert in which a chamfer having a width of 0.015 to 0.05 mm as viewed from the rake face side is formed on a cutting edge is disclosed.

The cutting insert of the present embodiment includes a base and a coating layer on at least a part thereof, and the base is made of one selected from a cemented carbide, a Ti-based cermet, or Si ₃ N ₄ or Al ₂ O ₃ . At least, the coating film is the outermost surface _{layer, TiC, TiN, TiCN, Al} 2 0 3, TiMN ( although, M is 4, 5, 6 metals of the periodic table excluding Ti, Al, selected from Si 1) and a diamond-like carbon layer, a polygonal first surface having a plurality of corners and a rake face, and a second face adjacent to the first face and having a flank face. has a face, a cutting edge located on at least a portion of the ridge line portion of the first surface and the second surface, and a nose portion located at the corner portion of the first surface, wherein the cutting edge, the located in the nose portion, the first further across the nose portion A first width is 5 μm to 30 μm in a front view of the first surface, and the chamfer angle is 35 °. It has a C plane of ５０50 °. The second cutting edge is located on the coating layer, and has a C-plane in which a second width of the first surface in a front view is equal to or less than the first width and a chamfer angle is 35 ° to 50 °.

  The cutting tool according to the present embodiment has the cutting insert mounted in an insert pocket provided at the tip of the holder.

  The method for manufacturing a cut workpiece according to the present embodiment includes a step of rotating the workpiece, a step of bringing the cutting blade of the cutting tool into contact with the rotating workpiece, and the step of cutting the cutting tool. Separating from an object.

It is an outline perspective view about an example of the cutting insert of this embodiment. FIG. 2 is a partial sectional view of the cutting insert of FIG. 1. (A) is a top view of the cutting insert of FIG. 1, (b) is a principal part enlarged view of (a). (A) is an enlarged view of a main part of another example of the cutting insert of the present embodiment, (b) is a side view of the cutting insert of (a) on the side of the transverse cutting edge, and (c) is (a). 3) is a side view of the cutting insert of FIG. (A) is an enlarged view of a main part of still another example of the cutting insert of the present embodiment, (b) is a side view of the cutting insert of (a) on the side of the transverse cutting edge, and (c) is ( It is a side view on the front cutting edge side in the cutting insert of a). It is a figure for explaining the manufacturing method of the cutting work in this embodiment, and Drawing 6A, Drawing 6B, and Drawing 6C are schematic diagrams for explaining each process. FIG. 6B is a schematic cross-sectional view of a portion A in the step of bringing the cutting blade of the cutting tool into contact with the workpiece in FIG. 6B.

  A cutting insert (hereinafter, referred to as an insert) 1 in FIGS. 1 to 5 has a first surface and a second surface adjacent to the first surface. In the present embodiment, the first surface 2 functions as a rake surface, and the second surface 3 functions as a flank. Hereinafter, the rake surface 2 and the flank 3 will be described. Further, at least a part of the ridge line between the rake face 2 and the flank face 3 functions as the cutting edge 4. The rake face 2 has a plurality of corners, and in the present embodiment, has a substantially polygonal shape. A curved nose portion 5 is located at a corner of the rake face 2. The cutting edge 4 has a first cutting edge 4a and a second cutting edge 4b with the nose portion 5 interposed therebetween. In the present embodiment, the first cutting edge 4a functions as a front cutting edge, and the second cutting edge 4b functions as a horizontal cutting edge. Hereinafter, the front cutting edge 4a and the horizontal cutting edge 4b will be described. . The flank 3 has a front flank 3a following the front cutting edge 4a and a lateral flank 3b following the lateral cutting blade 4b. In the present embodiment, the boundary between the front cutting edge 4a and the horizontal cutting edge 4b is defined as the point of the nose portion 5 farthest from the center of the rake face 2. At the center of the rake face 2, a through hole 6 for inserting a screw is provided.

  The insert 1 includes a base 8 and a coating layer 9 provided on the surface of the base 8, as shown in FIG. At least the front cutting edge 4 a is provided on the surface of the coating layer 9. In the present embodiment, the present invention is not limited to the case where the coating layer 9 is provided on the entire outer surface of the insert 1, and the surface of the base 8 becomes the rake face 2 or the flank 3. Is also good.

  As shown in FIG. 2, the front cutting edge 4 a in the present embodiment is located on the coating layer 9 and has a C surface 10 between the rake face 2 and the flank 3. The C plane 10 has a chamfer angle β of 35 ° to 50 °, and a first width L, which is a C plane width of the rake face 2 in a front view, of 5 μm to 30 μm. As a result, as shown in FIG. 7, a weld 7 is generated on the surface of the C-plane 10 when the insert 1 comes into contact with the workpiece, and the weld 7 protects the coating layer 9 from wear. Work as a membrane. Therefore, the wear of the coating layer 9 on the C surface 10 can be suppressed, and as a result, the wear resistance of the insert 1 can be suppressed.

  Here, in order to explain the positional relationship between the workpiece 22 and the C-plane 10, a method of manufacturing the workpiece by cutting the workpiece using the cutting tool 20 equipped with the insert 1 will be described with reference to FIG. It will be described based on.

  As shown in FIG. 6, in the cutting tool 20, an insert 1 is mounted in an insert pocket 21 provided at a corner of the tip of a holder 24. The holder 24 has a substantially quadrangular prism shape, and has an insert pocket 21 at a position opening to the side of the tip. Holder 24 is made of steel or hardened steel. The mounting surface (not shown) of the insert pocket 21 has a screw hole. The cutting tool 20 inserts the insert 1 into the insert pocket 21 by inserting a screw (not shown) from the rake face 2 side of the insert 1 and screwing the screw into a screw hole of the holder 24. It is attached.

Then, a cut product is manufactured by the following (i) to (iii).
(I) The cutting tool 20 is arranged above the prepared workpiece 22. Then, the object to be cut is rotated about the rotation axis O in the direction of the arrow r to bring the cutting tool 20 closer to the object to be cut 22 (FIG. 6A). Here, since the workpiece 22 and the cutting tool 20 only need to be relatively close to each other, the workpiece 22 may be brought closer to the fixed cutting tool 20.

  (Ii) The cutting tool 20 is brought closer to the workpiece 22 and the cutting edge 4 of the cutting tool 20 is brought into contact with a predetermined position on the surface of the rotating workpiece 22 to cut the workpiece 22. Process (FIG. 6B). At the time of cutting, first, the cutting tool 20 is brought into contact with the insert 1 mounted on the cutting tool 20 from a direction perpendicular to the side surface of the workpiece. At this time, the workpiece can be machined by sliding the cutting tool 20 parallel to the rotation axis of the workpiece 22. This is what is called turning. The cutting tool 20 is brought into contact with the workpiece 22 while being inclined at the specified side rake angle α.

  (Iii) The cutting tool 20 is separated from the workpiece 22 (FIG. 6C).

  Next, description will be made with reference to a schematic cross-sectional view of a portion A in FIG. 6B of FIG. The contact angle θ of the C surface 10 with the workpiece 22 is obtained by the inclination from the direction perpendicular to the finished surface of the workpiece 22. As shown in the schematic diagram of FIG. The contact angle θ with the workpiece 22 is α + β, which is the sum of the horizontal rake angle α of the holder 24 and the chamfer angle β of the C surface 10. The force that the C surface 10 receives from the workpiece 22 is the resultant force F of the feed component and the main component. Here, the smaller the difference between the angle (90 ° −θ) orthogonal to the C surface 10 and the angle of the resultant force F, the more easily the protective film is formed by the welded material 7 and the more easily the C film 10 is cut. The contact angle θ with the object 22 is 40 ° to 55 °. In the present embodiment, the chamfer angle β is 35 ° to 50 °, and generally, the side rake angle α is −5 ° to −6 °, so that the angle (90 ° −θ) orthogonal to the C plane 10 is: 40 ° to 56 °. Thus, in the insert 1 of the present embodiment, the angle between the angle (90 ° −θ) orthogonal to the C plane 10 and the direction of the resultant force F is zero or close to zero. Therefore, cutting is performed in a form in which the weld 7 is present on the C surface 10, and wear of the coating layer 9 existing on the C surface 10 is suppressed.

  That is, if the chamfer angle β is smaller than 35 ° or the chamfer angle β is larger than 50 °, the welded material 7 is not easily generated, and the wear of the coating layer 9 is likely to progress. Note that the chamfer angle β is an angle formed by the C surface 10 with respect to a ground plane (not shown) when the insert 1 is placed on the holder 24.

  If the first width L is smaller than 5 μm, the weld 7 is not easily generated, and the cutting edge 4 is easily broken. Conversely, if the first width L is larger than 30 μm, the cutting resistance increases and the wear progresses faster.

Further, in the present embodiment, in the front view of the rake face 2, the second width which is the width of the C-plane (hereinafter, referred to as a second C-plane for identification) of the horizontal cutting edge 4b is equal to the second width of the front cutting edge 4a. It may be smaller than one width. Note that the narrow cutting edge 4b than the first width in the second width before cutting edge 4a, the 2C surfaces have been formed, and a narrower than the first width. When such a configuration is satisfied, the welded material 7 does not adhere to or hardly adhere to the transverse cutting blade 4b, so that the sharpness is improved, and the finished surface of the workpiece 22 is smooth and free of fogging. State. Also, when the transverse cutting edge 4b is located on the coating layer 9, the above-mentioned configuration is satisfied, so that the welded material 7 does not adhere to the coating layer 9 or hardly adheres thereto. Thus, the finished surface of the workpiece 22 can be made smooth and free of fogging.

  As a method of changing the first width of the front cutting edge 4a and the second width of the horizontal cutting edge 4b, as shown in FIG. 4, the chamfer angles of the front cutting edge 4a and the horizontal cutting edge 4b are the same. A method of changing the depth and a method of changing the chamfer angle as shown in FIG.

  Further, in a front view of the rake face 2, the width of the cutting edge 4 may gradually decrease from the front cutting edge 4 a to the horizontal cutting edge 4 b via the nose portion 5. This gradually narrowing state is a configuration as shown in FIG. When such a configuration is satisfied, good wear resistance and a good finished surface are obtained. In the transverse cutting edge 4b, it is desirable not to provide the second C-plane, and when the width viewed from the rake face is 5 μm or less, in particular, the finished surface of the workpiece 22 should be in a smooth and cloud-free state. Can be.

  When the arithmetic average roughness on the flank 3 is smaller than the arithmetic average roughness on the rake surface 2, the amount of the welded material 7 generated on the C surface 10 becomes an appropriate amount and the finished surface of the workpiece 22 is reduced. Can be smooth. When the arithmetic mean roughness of the flank 3 is 0.01 to 0.1 μm, the finished surface of the workpiece 22 can be smoothed. When the arithmetic average roughness on the rake face 2 is 0.02 to 0.5 μm, the amount of the deposited material 7 is an appropriate amount.

  Further, the arithmetic average roughness of the rake face 2 and the flank face 3 can be adjusted by forming a coating layer 9 on the base 8 and then performing polishing from the surface of the coating layer 9. As the polishing, blasting or brushing is preferable. When blasting is employed, the arithmetic mean roughness on the rake face 2 and flank face 3 can be controlled by adjusting the position and direction of the nozzle for discharging the abrasive grains.

  In addition, suitable cutting conditions in the cutting tool 20 of the present embodiment include a cutting speed of 50 m / min to 250 mm / min, a cut of 0.05 mm to 3.0 mm, and a feed of 0.05 mm / rev to 0.4 mm / rev. It is. Under this condition, a weld 7 is easily generated on the C surface 10 during cutting.

  In particular, when the workpiece 22 is a low-carbon steel or an aluminum alloy steel, the deposition 7 is easily generated, and the wear resistance of the coating layer 9 is improved.

The coating layer 9 is made of TiC, TiN, TiCN, Al ₂ O ₃ , TiMN (where M is at least one element selected from metals of Groups 4, 5, 6 in the periodic table excluding Ti, Al, Si) and diamond-like carbon When at least one of the layers is contained, the surface of the coating layer 9 is smooth and the formation of the welded material 7 is likely to occur. In particular, when the outermost surface of the coating layer 9 is made of TiN or TiMN, the formation of a deposited material is likely to occur, and the wear resistance of the coating layer 9 is improved. The coating layer 9 may be a single layer or a multilayer of two or more layers.

On the other hand, the base 8 comprises a hard phase comprising tungsten carbide (WC) and, if desired, at least one selected from the group consisting of carbides, nitrides, and carbonitrides of metals of Groups 4, 5, and 6 of the periodic table. Cemented carbides or Ti-based cermets bonded by a binder phase composed of an iron group metal such as cobalt (Co) or nickel (Ni), or Si ₃ N ₄ , Al ₂ O ₃ , diamond, cubic boron nitride (cBN) ) Can be suitably used. Above all, it is desirable that the substrate 8 be made of a cemented carbide or cermet from the viewpoint of chipping resistance and wear resistance. Further, depending on the application, the base 8 may be made of a metal such as carbon steel, high-speed steel, or alloy steel.

  In order to manufacture the insert 1 of the present embodiment, first, a sintered body is formed by molding and firing a predetermined mixed powder. Next, after the surface of the sintered body is subjected to polishing such as double-end processing and outer peripheral processing as required, the ridge line portion is subjected to C-plane processing. As a specific method of C-plane processing, processing with a diamond grindstone and the like can be mentioned.

  Then, a coating layer 9 is formed on the surface of the obtained substrate 8 by a physical vapor deposition (PVD) method or a chemical vapor deposition (CVD) method. Further, the surface of the coating layer 9 corresponding to the C surface 10 is polished so that the C surface 10 becomes a smooth surface capable of promoting the formation of a protective film of the welded material 7, thereby further improving wear resistance. It becomes an excellent cutting insert.

  To a tungsten carbide (WC) powder having an average particle size of 1.5 μm, a metal cobalt (Co) powder having an average particle size of 1.2 μm was added and mixed at a ratio of 6% by mass, and the cutting insert shape was formed by press molding ( SNGN120408). The obtained compact was subjected to a binder removal treatment, and calcined at 1400 ° C. for 1 hour in a vacuum of 0.5 to 100 Pa to produce a cemented carbide. Furthermore, the produced cemented carbide was processed with a diamond grindstone.

  Next, a 4 μm-thick TiAlN layer on the C-plane was formed on the cemented carbide by the PVD method. 1-14 cutting inserts were produced. Then, for each sample, the chamfer angle in the C plane of the front cutting edge and the width of the C plane in the front view of the rake face, the chamfer angle in the second C plane of the horizontal cutting blade and the width of the second C plane in the front view of the rake face, The arithmetic average roughness on the rake face and flank face was measured.

The obtained insert was mounted on a holder having a lateral rake angle α of 6 °, and a cutting test was performed in the processing step of FIG. 2 under the following cutting conditions. The results are shown in Table 1.
Cutting method: Turning Workpiece: SCM435
Cutting speed: 200m / min Feed: 0.2mm / rev
Cut: 1.5mm
Cutting condition: Wet (using cutting oil)
Evaluation method: Cutting distance to flank wear 0.1mm (km)

  From the results shown in Table 1, Sample No. Sample No. 5 has a chamfer angle larger than 50 °, In No. 13, the chamfer angle was smaller than 35 °, and no weld material was generated on the C plane, and the cutting distance did not increase. In addition, the sample No. In No. 6, since the width of the C-plane viewed from the rake face side was smaller than 5 μm, chipping occurred in the cutting blade, and the cutting distance was shortened. Sample No. In No. 11, since the width of the C-plane viewed from the rake face side was larger than 30 μm, the cutting resistance increased, the flank wear became remarkable, and the cutting distance was shortened.

  On the other hand, the sample No. having a C-plane with a chamfer angle of 35 ° to 50 ° and a width of 5 μm to 30 μm as viewed from the rake face side. With respect to 1-4, 7-10, 12, and 14, it was confirmed that the cutting distance was increased. In particular, in sample No. 1 in which the first width at the front cutting edge is wider than the second width at the horizontal cutting edge. In Nos. 7 and 12, the processed surface roughness was also good. The sample No. In each of Nos. 7 and 12, the C-plane width was gradually reduced from the front cutting edge to the horizontal cutting edge via the nose portion.

  Sample No. 1 in which the arithmetic average roughness on the flank is smaller than the arithmetic average roughness on the rake face and the arithmetic average roughness on the flank is 0.01 to 0.1 μm. In Nos. 1 to 4, 7 to 9, and 12, the amount of weld deposits generated at the front cutting edge was appropriate, the cutting distance was long, and the processed surface roughness was good.

1 Insert (cutting insert)
2 rake face 3 flank 3a front flank 3b side flank 4 cutting blade 4a front cutting blade 4b horizontal cutting blade 5 nose part 6 through hole 7 weld 8 base 9 coating layer 10 C surface 20 cutting tool 21 insert pocket 22 cover Cutting object 24 Holder α Lateral rake angle β Chamfer angle θ Contact angle L with the object to be cut L First width (C plane width in front view of rake face)

Claims (11)

A substrate and a cutting insert including a coating layer at least partially,
The base is made of one selected from a cemented carbide, a Ti-based cermet, or Si ₃ N ₄ , Al ₂ O ₃ ,
The coating film, the outermost surface _{layer, TiC, TiN, TiCN, Al} 2 0 3, TiMN ( provided that at least 1 M is selected 4, 5, 6 metals of the periodic table excluding Ti, Al, of Si Species) and at least one of diamond-like carbon layers,
A polygonal first surface having a plurality of corners and having a rake surface, a second surface adjacent to the first surface and having a clearance surface, and a ridge line portion of the first surface and the second surface. A cutting blade located at least in part, and a nose located at a corner of the first surface,
The cutting edge is located at the nose portion, and further has a first cutting edge and a second cutting edge with the nose portion interposed therebetween,
It said first cutting edge, as well as positioned on the covering layer, the first width at the front view of the first surface is 5 m to 30 m, have a C-plane of the chamfer angle is 35 ° to 50 °,
It said second cutting edge, as well positioned on the covering layer, wherein it is second width at the front view of the first surface below the first width, chamfer angle is have a C-plane of 35 ° to 50 ° Cutting insert.   The cutting insert according to claim 1, wherein the first width is 15 µm or more.   The cutting insert according to claim 1, wherein the second width of the second cutting edge is smaller than the first width in a front view of the first surface.   The cutting insert according to any one of claims 1 to 3, wherein a width of the cutting edge in a front view of the first surface gradually decreases from the first cutting edge toward the second cutting edge.   The cutting insert according to any one of claims 1 to 4, wherein an arithmetic average roughness on the second surface is smaller than an arithmetic average roughness on the first surface.   The cutting insert according to claim 5, wherein the arithmetic average roughness on the second surface is 0.01 to 0.1 m.   The cutting insert according to claim 5, wherein an arithmetic average roughness on the first surface is 0.02 to 0.5 μm.   A cutting tool comprising the cutting insert according to any one of claims 1 to 7 mounted in an insert pocket provided at a tip of the holder.   9. A cutting method comprising: rotating a workpiece; contacting the cutting blade of the cutting tool according to claim 8 with the rotating workpiece; and separating the cutting tool from the workpiece. The method of manufacturing the workpiece.   10. The step of contacting the cutting blade, wherein a cutting speed is 50 m / min to 250 mm / min, a cut is 0.05 mm to 3.0 mm, and a feed is 0.05 mm / rev to 0.4 mm / rev. The method of manufacturing a cut product.   The method according to claim 9, wherein the workpiece is a low-carbon steel or an aluminum alloy steel.

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